THE USE OF ROTARY INSTRUMENTS IN ENDODONTIC THERAPY OF OLDER DENTAL PATIENTS
Burs (CJM Engineering). The respective use of
hand instruments may require extra working time.
It must however always be kept in mind that
when a patient is medically compromised, and
the basic principles of endodontic therapy
cannot be maintained, it would be better to avoid
endodontic treatment and modify the treatment
plan accordingly (17).
It should be highlighted that the reduction in
working time offered by the rotary systems
concerns solely the duration of mechanical
preparation. A common mistake that needs to be
avoided is the omission of an accepted amount of
irrigation, for the purpose of chemical disinfection
(18, 19).
1.3 Achieving patency
Secondary dentine deposition is continued
throughout one’s lifespan (24). It is therefore
expected that the root canals of elderly patients’
teeth are thinner compared to younger patients, to
a point that even after accessing them, achieving
patency is challenging. Moreover, tertiary dentine
is deposited over the root canal walls as a result
of the pulp reacting to multiple external stimuli.
The root canals in older teeth may be barely
visible or not depicted at all when observing the
preoperative x-rays (Fig.1). Figures 1 and 2 show
an older female patient’s tooth (#11) diagnosed
with symptomatic apical periodontitis. The root
canal was not visible either radiographically or
clinically without microscope magnification (Fig. 1).
The preparation was performed using NiTi rotary
instruments that helped both achieve patency and
shape the canal. Due to the patient’s orthopedic
problems, the transportation to the dental office
was very difficult; therefore the endodontic therapy
was completed in a single appointment (Fig. 2).
Patency is usually achieved with the use of small
file sizes (ISO #6, #8, #10), with a preference for
stainless steel files, due to more effective apical
transportation of the applied force. Special files have
been developed for this purpose with appropriate
design (i.e. PahtfinderS, C Files). However, the
use of rotary instruments with specific design to
achieve patency in the root canals (i.e. Pathfile,
ProGlider, and Dentsply) seems to have simplified
the procedure, ensuring acceptable results in less
time. The traditional patency achievement with
hand files has been occasionally shown to cause
significantly greater root canal transportation and
infraction of its original morphology as compared
to rotary instruments (25, 26).
1.2 Easier access to the root canal system
The access stage is the most important step in
endodontic therapy (20). vA common phenomenon
with geriatric patients is the obstruction of the root
canal orifices, due to the calcific degeneration
of the pulp chamber and the tertiary dentine
formation (17, 21). In many cases, calcification is
limited to the cervical third of the canal, resulting
in problems mostly in locating and preparing
the orifices and not in accessing the apical areas
(22). Orifice detection is traditionally achieved
with the use of the endodontic explorer DG16.
After the orifices have been located, access can
be achieved using rotary instruments and more
specifically with the help of GG burs, which are
recommended by various authors, since the early
years of Endodontology (23). Other burs can be
used as well, specifically designed for achieving
access to calcified orifices, such as the LN burs
(Maillefer, Denstply) and the Munce Discovery
2. Drawbacks of rotary instrumentation
2.1 Instrument separation
As mentioned earlier, older patients’ teeth often
present calcifications. Additionally, root canal
wall dentine, due to the physiologic process of
sclerosis with aging, displays increased hardness
and a high modulus of elasticity (27), which
impedes instrument rotation inside the root canal.
The root canal size reduction due to deposition of
secondary dentine (28), along with the common
calcification process, hampers access and
obstructs the clinician’s visual field. All the abovementioned factors, in addition to the lack of tactile
sensation in rotary systems and the increased
cutting efficiency compared to hand files, can lead
to iatrogenic events, especially in cases of limited
familiarity with their use (Fig. 3).
Many clinical studies have focused on the rotary
instruments separation and its prevalence
Figure 3 Instrument separation case in an older
patient’s tooth
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